Thiel Owners

I hasten to add that while the addition of Tom’s technical insight to Thiel excellence is equally fascinating and utterly insightful, I am a total ignoramus in this regard. Is it reassuring or disappointing that mere “consumers” can “get it” just by hearing them for the first time?

Hmmm....

Ob, the Mac you cite is current-limited by definition. If it doesn't double from 8 to 4, that means there is insufficient power to do so, whatever combination that power comes from storage capacitors (instantaneous) or transformers (sustained). Beyond that doubling, the power into 2 ohms is most germane. Many Thiel speakers dip near 2 ohms over extended ranges. You need at least 3x the 8-ohm power into 2 ohms and preferably a second doubling (4x).

Now, it's possible that you listen at low volume in a small, lively playback room . . . and less power is adequate . . . but, you're playing with fire if you ever wanted to crank it up. 

If I were looking, I would not put that Mac amp on my list due to self-admitted current limitation. 

I think there can be a little too much emphasis on doubling into 4 ohms.  This is related to gain and I think the total power of the amplifier is a better way to think about it.  There are well respected amplifiers that don't double.  Ayre, for example.  I'd consider two amplifiers that put out 300 watts/channel into 2 ohms comparable, even if one is rated 75 watts/channel and the other 100 into 8 ohms.  The 75 watt one doubles twice while the 100 watt/channel one only doubles once.  The 100 watt amp will, however, put out 75, 150 and 300 watts into 8/4/2 ohms.